Module to present and identify motor imagery tasks in electroencephalography

This work presents a module that aims to facilitate the acquisition of motor imagery tasks in electroencephalography (EEG) research. The device components are: a microcontroller which sets the time intervals of the events of a Graz type paradigm, and sends markers to an EEG acquisition system; a software that presents the visual and auditory clues of the paradigm in a personal computer (PC) for the test subject to perform the motor imagery tasks; and an algorithm aimed to extract the EEG information related to the motor imagery tasks. In the module validation, a delay of 1 ± 0.5 ms between the time in which the microcontroller marks the event in the EEG amplifier and the time in which the event is showed to the subject in the computer´s monitor was measured. Furthermore, an average difference of 167 μs was obtained between the time intervals theoretically set for every event and the time intervals obtained. The module was tested in the EEG acquisition of motor imagery tasks in a BCI research protocol involving thirty healthy subjects. The module was successful at presenting the paradigm in all the trials and in indentifying the events of each trial in the signals that were recorded.